Pneumatic drill.



No. 822,367. PATENTED JUNE 5, 1906. A. P.-HANSUOM.

PNEUMATIG DRILL.

APPLICATION FILED AUG. Z7, 1903.

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ADELBEHT P. HANSCOM, OF MALDEN, MASSACHUSETTS.

PNEUMATIC DRILL.

Speccation of Letters Patent.

Patented June 5, 1906.

Application filed August 27,1903 Serial N0.

To @ZZ whom t vta/y concern:

Be it known that l, ADELBERT P. HANS- ooM, a citizen of the UnitedStates, and residing at Malden, in the county of Middlesex and State ofMassachusetts, have invented an Improvement in Pneumatic Drills, ofwhich the following description, in connection with the accompanyingdrawings, is a specification, like characters on the drawingsrepresenting like parts.

This invention relates to pneumatic drills, and more particularly tothat type of such apparatus wherein a plurality of pistons and cylindersactuate, by or through suitable speed-changing mechanism, acentrally-arranged arbor by which the drill is carried.

One of the objects of my present invention is the arrangement of thevarious working parts of the apparatus in a compact, strong, and durablemanner, the engine or motor being so disposed with relation to thedrill-carrying arb or that maximum power may be imparted thereto with aneflicient balancing of parts.

Another object of my invention is the improvement and simplification ofthe valve mechanism which controls the ingress of the motive fluid toand its exhaust from the cylinders of the engine or motor.

Another'object of my invention is the production of a simple andconvenient reversing device to change the direction of rotation of thearbor.

The various novel features of my invention will be fully described inthe subjoined specification and particularly pointed out in thefollowing claims.

Figure l is a vertical sectional view of a pneumatic drill embodying oneform of my invention, taken on the line l 1,Fig. 2, a por-v tion of thetransmitting-gearing and the arbor being shown in elevation. Fig. 2 is avertical section in a plane at right angles thereto on the irregularline 2 2, Fig. l, looking toward the left with 'the arbor in elevation,the engine-pistons being shown at full stroke, as in Fig. l. Fig. 3 isan enlarged detail in plan and partly broken out, showing the reversingmeans for the engine. Fig. 4 is sectional detail thereof on the line 44, Fig. 8, looking toward the left. Fig. 5 is an enlarged longitudinalsection on line 5 5, Figs. 6 and 7, of the means for controlling thepassage of motive fluid to and from the cylinders andi which also servesas the common fulcrum or? trunnion on which the cylinders oscillate, the

i the cylinders, the latter being shown at halfstroke. Fig. 8 is adetail in elevation and part section of the center bearing for thecrank-shafts of the motor.

In the present embodiment of my invention the motor and transmittingmechanism are inclosed within a case comprising a top portion A, havingparallel end walls a a, Fig. l, and oppositely-sloping side walls a a,joined at their upper ends by an arched portion ax and connected attheir lower ends by suitable means, as screw-bolts au, with thecasing-bottom A20, the bolts passing through circular llanges 75 and 76on the casing top and bottom portions, respectively.

The top portion A is strengthened by a central web a2, parallel to theend walls and extended from one side wall part way across the portion A,the web being provided with a suitable seat a3 for a bearing for theinner adjacent and alined ends of two crank-shafts c c, (see Fig. 1,)the outer ends of .said shafts being supported in bearings a7 a, shownas thimbles held jointly by the top and bottom members of the case andpreferably provided with antifriction-rolls 7, Fig. l.

Each thimble has a ilanged head 8 and a lateral annular flange 9 at itsinner end, the flanges entering correspondingly-shaped seats in thecasing and cooperating with the flanged heads 8 to retain said bearingsfrom longitudinal movement.

Referring to Figs. 1 and 8, the center bearing is shown as comprisingtwo bushings a4, set into the seat a3 from opposite ends and havingflanged heads a5 to enter the counterbored ends of the seat, the innerends of the bushings abutting, and separate disks a iit into said innerends to form a backing for the antifriction-rolls a7, surrounding theends of the crank-shafts. The two crank-shafts are thus alined andlocated on opposite sides of the central web a2, each one having abevelpinion, as GX cX, secured thereon adjacent the inner ends ofthethimbles or bushings a7 a, respectively, while collars 70 and 71 on theshafts abut against the outer ends of the bushings a4.

The bottom portion A20 of the casing is circular in cross-section andtapers toward its IOO IIO

lower end, terminating in a cylindrical boss @15, provided with aninternal annular shoulder a,16 and having a plurality of externalradially-extended ears a, shown in Figs. l and 2 as connected with theportion A20 by strengthening-webs als.

A bushing bx, having an external annular shoulder b to seat on theshoulder als, is inserted in the boss @15 into the position shown bestin Fig. l, the upper end of the bushing only partly filling the bossabove the shoulder 01,16, andan internal annular shoulder b is formed inthe bushing.

yThe tool-carrying arbor B, internally recessed at b2 to receive theshank of the drill or other tool, enters the bushing b with a runningiit and has an annular enlargement b3 to seat on the shoulder b of saidbushing.

Above the enlargement b3 the arbor is reduced in diameter at b4 to enterthe hub c2 of a large bevel-gear C2 in mesh with the bevelpinions 0X cX,a key b5, Fig. l, being employed to rigidly connect said gear with thearbor to rotate in unison.

The extremity of the arbor above the part b4 is still further reduced indiameter, as at b, and it enters a socket L19 in the bottom of the seat0,3, said socket being counterbored at a2". (Shown most clearly in Fig.8.)

The counterbore L20 serves to position a hardened-steel disk a, formingone half of a raceway for a series of balls 2l, the disk being pinned tothe bottom of the seat a3 at 22, (see Fig'. 1,) while the other half ofthe raceway is shown as a' disk @22, also of hardened steel, pinned at23 to the top of the hub c2, the part b6 of the arbor passing looselythrough both disks, the pin 23 being dotted in Fig. 2.

As will be manifest, the disks and balls form an antifriction end-thrustbearing for the arbor, the thrust being transmitted through the seat a3to and being taken up by the web a2.

Referring to Figs. l and 2, it will be seen that the externall-cylindrical base of the hub c2 iits into the boss @15 above the top ofthe bushing b and rests u on the latter the sides of the boss affordinga lateral bearing to assist in positioning the hub.

A strengthening-ring L25 is secured by bolts a2 to the ears a, said ringsurrounding the lboss @15 near its lower end and serving to stiHen andstrengtheny it, this ring being removed when the angle attachment isapplied, as will be described.

In order to prevent any binding of the gear C2 by or through end thrustof the arbor, the bottom of the gear-hub is slightly recessed at 24,Fig. l, above the enlargement b3 of the arbor, the thrust beingtransmitted from the upper end of part b4 of the arbor to thethrustbearing.

Inasmuch as the bevel-pinions engage the gear C2 at diametricallyopposite points, it is necessary to provide two separate crankshafts,rotating oppositely, as herein shown, the direction of rotation of thegear C2 being indicated by the arrow 26, Fig. 2.

The pinions and bevel-gear form transmitting means intermediate themotor or engine, to be described, and the tool-carrying arbor B.

The end walls a and a are provided with two opposite circular aperturesbored to provide true bearing-surfaces for the valve structure, whichlatter also constitutes a trunnion or support on which the cylinders ofthe motor are mounted to oscillate, the apertures being surrounded byinternally-threaded nipples aa" @31, respectively, Fig. l.

Threaded plugs da() dsl are screwed into said nipples after the trunnionis in place, preventing longitudinal movement thereof, the plug ab beingsolid, while plug 0331 has a passage 32 through it to admit motive iuid,such as compressed air, to the apparatus, the outer end ofthe passageregistering with the upper end of a conduit @32 in the wall a.

An inlet-pipe @33, Fig. l, communicating with the lower end of theconduit, conducts motive fluid thereto from any suitable source ofsupply.

The construction of the trunnion is best shown in Figs. l and 5.

Two cylindrical tubes g and b, having a common bore, are driven tightlyinto outer tubes gX hX, respectively, the outer tubes having their innerends butted` together, while one of the inner tubes, as g, iscounterbored at its inner end, as at g/, to snugly receive the reducedend b of the tube h, one of said tubes being capable of rotativemovement, however, relative to the other.

Before assembling the tubes g and 71, are externally cut away for a partof their length and extending nearly around their outer circumferences,leaving clearance-spaces g2 b2 between the inner and outer tubes, thelatter being provided with holes g3 b3, respectively, communicating withthe clearances, which constitute exhaust-chambers. As shown in Figs. land 5, the end of the tube g adjacent the plug d3 is closed, as at g3".

The mode of construction described is very simple and convenient, astrong and eflicient trunnion and valve being provided at small cost.

An elongated inlet-port is'made in each section or half of the trunnion,the ports being shown at g4 b4 in Figs. 6 and 7, respectively, andestablishing communication between the bore I of the trunnion, which maybe termed the inlet-chamber, and the exterior of said trunnion, eachport extending from the chamber l through the outer tubes gX and bx,respectively.

On opposite sides of and adjacent the said ports the tubes g and b,X areeach provided with two ports, as g5 96 and b5 h6, (shown in Figs. 6 and7,) communicating with the exhaust-chambers g2 b2, respectively.

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cease? Upon the trunnion are vibratorily mounted and suspended the twincylinders C C, having equal length and diameter and provided withsuitable pistons P P', respectively, Fig. 1, the piston-rods p p beingshown as rigid with or forming part of the pistons and extending outthrough the lower open ends of the cylinders. The upper ends of thelatter are closed with the exception of ports 50 51, (see Figs. 6 and7,) and said ends are provided with tubular extensions C10 C11 whichsurround the trunnion with an easy but steam-tight fit to rockthereupon. lt will be understood that the several inlet and exhaustports formed in the trunnion are elongated to conform to the length ofthe ports 50 or 51 in the cylinder ends, the cylinders by theiroscillation moving their ports into and out of register with the portsof the valve structure or trunnion. Each end of the latter is thusprovided with three portsa central one for the admission of motive fluidto a cylinder and one on each side for the exhaust.

The material of the outer tubes g or hX, which separates the centralinlet-ports from the contiguous exhaust-ports, is of such width in eachinstance as will just cover the port in the cylinder.

inasmuch as the crank-shafts rotate in opposite directions, thecylinders will vibrate or oscillate in the same direction rather thanoppositely, as would be the case if the crankshafts were connected androtated in the same direction.

Vhen the two pistons are at full stroke, as in Fig. 1, the cylinderswill be up and down and the two cranks one hundred and eighty degreesapart, while at half-stroke the cranks will be just passing each otherand the cylinders will be inclined at one or the other side of thevertical axis of the apparatus.

In Fig. 7 the piston of the cylinder C is supposed to be at half-stroke,the cylinder taking motive iiuid through ports h4 and 51, and when theoutward stroke is completed and the inward stroke begins the port 51will begin to register with the exhaust-port h5.

As to cylinder C, from Fig. 6 it will be manifest that its piston is atmid-stroke, the cylinder exhausting through ports 50 and g5, the pistonbeing on its inward stroke.

The exhaust is discharged through the ports or outlets g3 h3 into thecasing and escapes thence to the outer air by means of an outlet-nippleEX, Fig. 2.

The ports g6 and h6 are utilized when the valve structure is shifted toreverse the motor, so that the arbor-gear C2 and arbor B will be rotatedoppositely to the arrow 26, Fig. 2.

Vhen the motor is to be reversed, by means to be described theright-hand half of the valve structure, Fig. 1, will be partly turned indirection of arrow 100, Fig. 7, while turned oppositely in direction ofarrow 101, Fig. 6, it being remembered that Figs. 6 and 7 are viewedfrom opposite ends of the valve structure.

The top portion A of the casing is provided with a housing A5, Figs. 2,3, and 4, extended laterally from the wall du and surmounted by aninternally-threaded boss as@ in alinement with'the arbor B for a purposeto be described, the housing opening into the interior of the casing, asat 85, Fig. f1.

Collars gS hs are secured to the tubes g and h at opposite sides of thesleeve-like center bearing a for the valve structure, (see Fig.1,)formed in the web a2, each collar having a threaded boss 63, Fig. 1,to receive the threaded end 64 of a reversing-arm, said arms g9 h" beingclearly shown in Figs. 2 and 3 and slightly tapered, as at 65, beyondthe thread to pass through a hole in the outer tube and enter a socketg10 or hw in the inner tube. By thus engaging both tubes of a pair theyare turned in unison without any twisting strain, though it will beunderstood that the two tubes are rigidly secured together by forcingthe inner one into the outer one.

The reversing-arms extend from the valve structure at right anglesthereto and pass through the housing A5 into a chambered cover-plate A6,detachably held in place by suitable screws 200, Fig. 8, the cover-platehaving a central bearing-boss 201 and an external flange 202 for alpurpose to be described.

The central solid portion of the housing is provided with a socket 203Fig. 3, for the inner end of a stud rx, rotatably mounted in the boss201 and projecting therethrough into the space inclosed by theA flange202, a handle 1 of any suitable construction being secured to the stud.

Between the boss 201 and the adjacent end ICO ` the stud, said blockhaving elongated eyes r2 on opposite sides to receive loosely the freeends of the reversing-arms g 7L, so that by turning the stud by means ofthe handle r/ the said arms willbe moved oppositely. Such movement ofthe arms turns the two halves of the valve structure in oppositedirections to reverse the operation of the motor-that is, if the valvestructure is in the position shown in Figs. 6 and 7 and thereversingstud rx is turned the valve halves'will be turned to bring theexhaust-ports g6 and h into op erative position and render the ports g5h5 inoperative. Thus by a turn of the hand the operator can reverse themotor, the flange 202 acting as a shield for the handle r2 andpreventing the stud TX from being turned accidentally.

As shown in Fig. 3, the inner face of the yoke-block 1" has two pits ordepressions therein, as 1", and the solid center of thehoussimultaneously the left-hand half will be l ing A5 is recessed ateach side of the center at ITO T5, each to receive a locking bolt orplunger r, pressed outward by a spring r3 and having a pointed orconical top rs.

The depressions r4 are so located on the block that when the stud rx isin position for forward or backward operation one of the bolts r willenter a depression and hold the stud in the proper position. Thelockingbolts thus indicate to the operator when the valves are in thecorrect position, as at such time one or the other of said bolts willsnap into its depression r4.

The internally-threaded boss aso, Fig. 1, is

socketed to receive the inner end of a threaded stud (182, having anannular flange 0,83 fast upon it to enter the boss, a heavyretainingbushing ai being screwed into said boss and bearing upon theiiange (1,83, so that the stud (182 is rigidly held in position and inalinement with the axis of the arbor B. An internally-threaded backcenter L85 is screwed upon the stud and provided with handles a8, bywhich it may be more readily revolved, the operation of the back centerbeing familiar to those skilled in the art and requiring no furtherdescription.

Opposite the inlet 1,33 the part A of the casing is provided with a hubor boss a, into which is screwed a handle-bar am, (see Fig. 1,) by whichthe positioning of the apparatus is facilitated.

The free ends of the piston-rods p p are enlarged, as at 23202921,respectively, Fig. l, to support bearing-boxes of any suitable characterfor the cranks of the two crank-shafts, boxes provided with rolls orsimilar antifriction means being preferable.

From the foregoing description, in connection with the drawings, theoperation of the apparatus will be readily understood, the transmittingmeans intermediate the crankshafts and arbor acting also as aspeed-reducer, so that the engine or motor may be run at high speed.

The construction is simple, compact, and efficient, the power beingapplied to the large gear C2 at two diametrically opposite points, andthe support for the arbor both as to end thrust and lateral bearings isstrong and rigid.

Having described my invention, what I claim as new, and desire to secureby Letters Patent, is-

1. In apparatus of the class described, a casing, an arbor rotatablymounted in and extended through one end thereof, a pair of oscillatingcylinders each having a piston, a combined trunnion and valve structuresupported within the casing and on which the cylinders are mounted sideby side, at their ends, two separate crank-shafts operatively connectedwith the pistons and mounted in alinement, a pinion on each crank-shaft,and a gear operatively connected with the arbor and with whichsaidpinions mesh at diamet= rically opposite points.

2. In apparatus of the class described, a casing, an arbor rotatablymounted in one end thereof, a pair of oscillating cylinders each havinga piston, a combined trunnion and valve structure supported within thecasing and on which the cylinders are mounted side by side, twocrank-shafts operatively connected with the pistons and mounted inalinement, a pinion on each crank-shaft, a gear operatively connectedwith the arbor and with which the pinions mesh at diametrically oppositepoints, a central web in the casing, between the cylinders, a bearing onsaid web for the center of the trunnion, and a second bearing sustainedby the web for the inner ends of the crank-shafts.

3. .ln apparatus of the class described, a casing comprising separabletop and bottom portions, the former having an integral central web andthe latter having a boss at its end, a combined trunnion and valvestructure supported by the casing top and web, transversely to thelatter, oscillating cylinders mounted at their ends on said trunnion atopposite sides of the web and each provided with a piston, a centerbearing sustained by the web, a plurality of alined and independentcrank-shafts operatively connected with the several pistons andsupported at their adjacent ends in said center bearing, bearings forthe outer ends of the shafts, mounted j ointlyv in the top and bottom ofthe casing, an arbor rotatably mounted in the boss of the casing-bottom,and transmitting means intermediate the crank-shafts and arbor, torotate the latter.

4. In apparatus of the class described, a casing comprising separabletop and bottom portions, the former having an integral flat central weband the latter having a boss at its end, crank-shaft bearings mountedjointly in said parts of the casing, a center bearing on the web, aplurality of oscillating cylinders mounted within the casing-top andeach provided with a piston, a plurality of independent crank-shaftsoperatively connected with the pistons and mounted at their inner endsin the center bearing, the outer ends of the said shafts entering thebearings in the casing, an arbor rotatably mounted in the boss of thecasing-bottom at right angles to said crank-shafts, transmittingconnections between the latter and the arbor, to rotate the latter, andmeans to govern admission of motive fluid to and exhaust thereof fromthe cylinders.

5. In apparatus of the class described, a two-part casing, a flatcentral web in one of said parts, a pair of oscillating cylindersmounted in said part on opposite sides of the web and each provided witha piston, independent crank-shafts operatively connected IOO IIO

with the istons and arranged in alinement, bearings 'or their outerends, on the casing, a common bearing for their inner ends, carried byand transverse to the web, an arbor rotatably mounted in and extendedthrough the other part of the casing at right angles to thecrank-shafts, an end-thrust bearing for the arbor, sustained by the web,immediately adjacent the crank-shaft bearing, and gearing intermediatethe crank-shafts and arbor to rotate the latter.

6. In apparatus of thel class described, a two-part casing, a centralweb in one of said parts, a pair of oscillating cylinders mounted insaid part on opposite sides of the web and each provided with 'a piston,independent crank-shafts operatively connected with the pistons andarranged in alinement, bearings for their outer ends, on the casing, anarbor rotatably mounted in and extended through one part of the casing,a gear connected with the arbor and rotating therewith, and a pinion oneach crank-shaft, 1n mesh with the gear, said pinions engaging thelatter at diametrically opposite points, the crank-shafts rotating inopposite directions.

7. In apparatus of the class described, a two-part casing, a central webin one of said parts, a pair of oscillating cylinders mounted in saidpart on opposite sides of the web and each provided with a piston,independent crank-shafts operatively connected with the pistons andarranged in alinement, bearings for their outer ends, on the casing, aseat on the web roller-bearings mounted thereon for the inner ends ofthe crank-shafts, an arbor rotatably mounted in and extended through thebottom part of the casing at right angles to said crank-shafts, anattached gear, a ballbearing interposed between the arbor and the seat,to take up end thrust of the arbor, and a pinion on each crank-shaftnear its outer end, in mesh with and to rotate the arbor-gear at reducedspeed.

8. In apparatus of the class described, a casing, an arbor rotatablymounted` in the bottom thereof, a gear keyed to said arbor within thecasing, an engine mounted in the top of the latter and comprising twooscillating cylinders arranged side by side, each provided with apiston, a tubular extension at one end of each cylinder, having a portinto the cylinder, means to rotate said gear by or through reciprocatingmovement of the pistons, and a combined trunnion and valve structure forthe cylinders, comprising two alined and relatively rotative tubesconstituting an inlet-chamber and provided with outlet-ports, an outertube on and iixed to each of said tubes with an annular clearancetherebetween to constitute two separate exhaust-chambers, and an inletand an outlet port for each, the outlet-ports opening into the casing,the inlet-port of each exhaustchamber being adapted to coperate with thecylinder-port alternately with the outletport of the inlet-chamber, thetubular extensions of the cylinders surrounding the outer tube of eachpair of tubes.

9. In apparatus of the class described, a casing, a trunnion mountedtherein, and comprising two pairs of tubes in alinement and sleevedtogether, the two inner tubes communicating and constituting aninletchamber, the outer tubes being secured to their inner tubes withannular clearances between them to constitute two exhaust-chambers, eachouter tube having an inlet-port communicating with the inlet-chamber,and two exhaust-ports on opposite sides of said inlet-port, each pair ofexhaust-ports communicating with an exhaust-chamber, a cylinder mountedto oscillate on the outer one of each pair of tubes and having a singleport, an arbor rotatably mounted in the casing, pistons for thecylinders, crank-shafts with which they are operatively connected,gearing between the crank-shafts and arbor to rotate the latter, andmeans to effect opposite angular movement of the two pairs of tubesconstituting the trunnion, to eliect reversal of the engine, andconsequently reverse the rotation of the arbor.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

ADELBERT P. HANSCOM.

Witnesses:

JOHN C. EDwARDs, MARGARET A. DUNN. jfl

